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TOOTH SEPERATION& MATRICINGPresented by Amjath kMalabar dental college

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INTRODUCTION

DEFNITIONS

NEED FOR TOOTH SEPARATION

METHODS OF TOOTH SEPARATION

MATRICING2

INTRODUCTIONSeperation of teeth may be necessary inorder to-

Improve convenience form of dentist

Prevent damage to teeth & supporting tissues

Achieve functional contacts,contours & occlusion during restorations.3

Tooth movement or separation of teeth can be defined as the process of separating the involved teeth slightly away from each other or bringing them closer to each other or changing their spatial position in one or more dimensions..DEFNITION4

NEED FOR TOOTH SEPARATION1.DIAGNOSIS of initial proximal caries not seen on radiograph

2.CAVITY PREPARATION- adequate access in class11 & class111 cavity preparation

3.MATRIX PLACEMENT

4.POLISHING RESTORATION-polishing proximal surfaces of class111 & class1V restoration

5.REPOSITIONING DRIFTED TEETH6.REMOVAL OF FOREIGN OBJECTS5

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METHODS OF TOOTH SEPARATIONSlow or delayed separation.

Rapid or immediate separation.

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SLOW OR DELAYED SEPARATIONCauses slow movement of teeth over a period of several days or weeks

Indications- tilted,drifted or rotated tooth in which rapid movement is not possible

Advantage- no periodontal damage

Disadvantage- time consuming & require many visits7

Methods of achieving slow separation1 Separating rubber rings or bands

2 Rubber dam sheet

3 Ligature wire or copper wire

4 Gutta percha sticks

5 Oversized temporary crowns

6 Fixed orthodontic appliance

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Separating rubber ring or band

Used in orthodontic cases

It is stretched and placed interproximally between two teeth to achieve seperation

It may take 2-3 days to 1 week.

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Rubber dam sheetIt is stretched and placed interproximally between the teeth

Usually heavy or extra heavy type is preferred

Time for separation varies from 1hr to 24 hrs

In case of pain or swelling a floss may be used to remove the sheet

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LIGATURE WIRE OR COPPER WIREWire is passed beneath the contact area to form loop

Tightening done by twisting two ends together.this causes increase in separation.

Separation achieved in 2-3 days

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Gutta percha stickIt is softend with heat and packed into proximal area.

Usually indicated in posterior teeth

Tooth separation usually takes 1to 2 weeks

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Over sized temporary crownsTemporary crowns are made oversized in the mesiodistal dimensions and periodically resin is added to the contact area to increase the amount of separation.

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Orthodontic appliancesIndicated only when extensive repositioning of tooth required

Most predictable and effective method..14

RAPID OR IMMEDIATE SEPARATIONHere tooth movement achieved rapidly over a short period of time

It is achieved by two methods

Wedge principle

Traction principle15

1.Separation by wedge principleA pointed wedge shaped device is inserted between teeth to produce the desired amount of seperationeg elliots seperator, wedges.

1. ELLIOTS SEPARATOR

Also known as crab claw separator because of its design.Mechanical device consisting of-bow-two holding jaws-tightening screw

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Separation should not be more than thickness of pdl, ie,0.2-0.5mm

Used for examination and polishing of final restoration.

Clockwise rotation of tightening screw moves contacting teeth apart

Two holding jaws are positioned gingival to the contact area without damaging the interproximal area17

WEDGESWedges are devices that create rapid seperation during tooth preperation and restoration

Functions of wedges

Help in rapid seperation of teeth

Prevent gingival overhang of restoration

Provide space for compensate thickness of matrix band

Help in stabilization of retainer and matrix during restorative procedures

Help in retracting and depressing interproximal gingival area thus help in minimizing trauma to soft tissue.

Help in depressing rubber dam in interproximal area

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Wedges made of two materials

Wood or plastic

1.Wooden wedges

Soft wood like pine or hardwood like oakThey may be medicated

They are prefered because-

Easy to trimAdapt wellAbsorb moisture and swells to provide adequate stabilization to matrix bandThey are used along with metal matrices

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Wooden wedges can be of two shapesTriangular or round

Triangular wedges are commercially available

Prefered for cavities with deep gingival marginIt has got an apex and a base

Apex usually lies in the gingival portion of contact area.Base lies in contact with gingiva ,this helps in stabilization and retraction of gingiva

Used in tooth preperation with deep gingival margin.

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Round wedge

-Made from wooden tooth picks by trimming the apical portion

-It has a uniform shape

-Used in class11 tooth preparation21

Plastic wedges

Commercially available

Used with either transparent matrices or metal matrices

They cannot be trimmed & thus cannot be custom fit.22

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Special plastic wedges which are transparent and have a light reflecting core

Used with transparent matrices while placing class11 composite restoration.

Transmits 90-95% incident light

It helps in reducing polymerization shrinkage as it transmits light.

Better adaptability

Light transmitting wedges.

PLACEMENT AND LOCATION OF WEDGESCorrect location of the wedge is in the gingival embrasure below the contact area,Select the appropriate wedge depending on the clinical situationWooden wedges can be trimmed with a knife or scalpel to produce a custom fitWedge is usually placed from the lingual embrasure which is normally larger in sizeIf it interferes with tongue it can be placed from buccal side.Length of the wedge should be only 0.5inch or 1.3cm so that it does not irritate tongue or the cheek.After placement wedge should be firm and stable.

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Modified wedging techniquesDouble wedging

Two wedges are usedOne inserted from buccal embrasure and another inserted from lingual embrasure

Indication: large spacing between adjacent teeth where single wedge is not sufficientWidening of proximal box in buccolingual dimension

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Wedge wedging

Two wedges are usedOne wedge is inserted from lingual embrasure area while another inserted between wedge and matrix band at right angle to first wedge.Primarily indicated while treating mesial aspect of maxillary first premolar.These tooth have flutes(concavities) in root near gingival area.

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Piggyback wedging

Two wedges are usedOne larger wedge is inserted as normally ,while the smaller wedge(piggyback) inserted above the larger one.Indicated in case of shallow proximal box with gingival recession.This technique provides closer adaptation and contour of matrix band.

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2.Separation by traction principle

This employs a mechanical device to engage the proximal surfaces of contacting teeth and bodily moves them apart to bring about seperation.

eg: ferriers double bow seperator

This mechanical device has two bows.

The jaws of each bow engages the embrasure of the contacting teeth gingival to contact area

A wrench is used to turn the threaded bars slowly to create adequate separation

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Impression compound is used to stabilize the bows on the teeth

Separation is achieved at the expense of both contacting tooth rather than one tooth.

Tooth preperation,finishing & polishing of class111 direct gold restoration

Ferrier bow separator

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MATRICINGDEFINITIONS

Matricing -is the procedure whereby a temporary wall is created opposite to axial walls, surrounding areas of the tooth structure that were lost during cavity preperation

Matrix-is a device used during restorative procedures to hold the plastic restorative material within the tooth while it is settingIntroduced by Dr. Louis Jack in 1871 30

Ideal requirements of a matrixEase of application-

Ease of use- the retainer or its handle should not interfere with the condensation of the restoration or patient comfort

Ease of removal

Rigidity-the matrix should be rigid enough to confine the restorative material as it is condensed under presssure and should not get displaced easily from its position

Provide proper proximal contact and contour.31

Positive proximal pressure-the matrix should exert a positive pressure against the adjacent tooth during insertion of the restoration so that after its removal normal contact between teeth is established

Non reactive-it should not react or stick to the restorative material.

Inexpensive

Easy to sterilize

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Functions of matrixTo confine restorative material while it is hardening.

To establish optimal contacts and contours for the restoration.

To prevent gingival overhangs of restoration.

To provide acceptable surface texture for restoration.33

Parts of matrix

Retainer-it holds the band in desired position and shape.

It may be a metallic ring, mechanical device, dental floss or impression compound.

Band-It is a piece of metal or polymeric material used to give support and give form to the restorative material during its insertion and hardening.

Commonly used materials for matrix bands are

Stainless steelPolyacetateCellulose acetateCellulose nitrate

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The bands are usually available as strips of various dimensions 0.001-0.002 inch thickness

Width- 3/16 or th inches for permanent teeth5/16th inch width for deciduous teeth

Matrix band should extend 2mm above marginal ridge height and 1mm below gingival margin of the preparation.

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Classification of matrices

Depending on type of band material

Stainless steelCopper bandCellulose acetatePolyacetate

Depending on its preparation

Custom made or anatomic matrix eg; compound supported matrixMechanical matrix eg; ivory no.1 and ivory no.8

Depending on mode of retention1.with retainer eg: tofflemire, ivory no.1 and ivory no 8 matrices2.without retainer eg: automatrix36

Depending on cavity preparation for which it is used

Class1 cavity with buccal or lingual extension.

Double banded tofflemire matrix

class11 cavity

Single banded tofflemire matrixIvory no.1 & ivory no.8Compound supported matrixT-band matrixAutomatrix

class111 cavity

S-shaped matrixCellophane stripsMylar strips

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Class IV cavity

Cellophane stripsTransparent celluloid crown formsDead soft metal matrix strips

Class V cavity

Window matrixTin foil matrixPreformed transparent cervical matrix

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Description of various matricesIvory no.1 matrix.

This matrix consists of a stainless steel band which encircles one proximal surface of a posterior tooth.

This is attached to the retainer via a wedge shaped projection.

An adjusting screw at the end of the retainer adapts the band to the proximal contour of the prepared tooth

As the adjusting screw is rotated clockwise the wedge shaped projections engage the tooth at the embrasures of the unprepared proximal surface39

Indications

For restoring a unilateral class11 cavity especially when the contact on the unprepared side is very tight

AdvantagesEconomicalCan be sterilized

DisadvantageDifficult to apply & remove

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2 .Ivory no 8 matrix

This matrix consists of a band that encircle the entire crown of tooth

The circumference of the band can be adjusted by adjusting screw present in the retainer

Indications

Unilateral & bilateral class11 preparation(MOD)

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3 .Tofflemire matrix

Designed by Dr BF Tofflemire.Also known as Universal matrix as it can be used in all types of tooth preparation of posterior teeth.

Indication

Class1 buccal or lingual extensions

Unilateral or bilateral class11(MOD) tooth preparation

Class11 compound tooth preparation having more than two missing walls.

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Advantages

Ease of useProvide good contact & contour for most amalgam restorationRigid & stable

Disadvantages

Does not provide optimum contour & contact for posterior composite restorationsNot useful for extensive class11 restoration.

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Parts of tofflemire retainer

Head: this part accomadates the matrix band.It is u-shaped with two slotsThe open side of the head should be facing gingivally when band is placed around the tooth

Slide(diagonol slot): amount of band extending beyond the slot depends upon type of tooth to be treated.This portion is located near the head for installation of band in retainer,helps in placement of band around the tooth.44

Knurled nuts

1.Two knurled nuts in retainera- large knurled nut-near the matrix bandAlso known as rotating spindle

Helps in adapting the loop of matrix band against the toothHelps in adjusting the size of loop of matrix band against the tooth.

b-small knurled nutHelps in tightening the band to the retainer

Assembly of retainerThe loop extending from retainer can project in following ways

straight-used near anterior teethleft/right-used mostly in posterior areas of oral cavity.

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Types of bands

Two types of bands are usually used1. Flat bands2.Pre contoured bands

Flat bandsAvailable in two thickness0.0020 inches0.0015 inches

Available in 3 shapes No1 universal bandNo2 or MOD band used in molarsNo 3 narrower than no 2

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Tofflemire retainerAvailable in two sizesStandard for use in adult dentition.Small for use in primary dentition.48

OPERATIVE INSTRUCTION FOR PLACEMENT

First open the large knurled nut so that the slide is atleast inches from the head.Hold the knurled nut (large) with one hand ,open the small nut in opposite direction for clearence of diagonal slot for reception of matrix bandTwo ends of matrix band are secured together to form loop or either form preformed loopPlace the ends of band in diagonal slotThen small knurled nut is tightened to secure the band to the retainer.After securing the band tightly to the retainer it is placed around the tooth to be restoredFor final adaptation of matrix band to tooth, tighten the large knurled nutWedge placement: wedge should be placed after the retainer and band fitted to the tooth. always insert the wedge from widest embrasure area 49

Procedure for removal

Removal of retainer

Small knurled nut is moved counter clockwise to free the band from the retainerWhile rotating the smaller knurled nut,hold the larger nutKeep the index finger on the occlusal surface of band to stabilize the band

Removal of band

Carefully remove band from each contact pointSupport the occlusal surface of restoration.while removing the band a condensor can be held against the marginal ridge of restorationDo not pull band in occlusal direction rather move the band in facial or lingual directionBand can be cut near to the teeth on the lingual side and try to pull it from buccal side.

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4.Compound supported matrix ,custom made or anatomical matrix.

Introduced by sweeney.

It is entirely hand made and contoured specifically for each individual.

Employs a 5/16th inch wide,0.002 inch length stainless steel band.

The band is contoured with an egg shaped burnisher on a paper pad to achieve the approximate proximal as well as facial and lingual contours of prepared tooth.

The band is positioned and stabilized by applying softened impression compound facially,lingually and occlusally over the occlusal surface of adjacent tooth.

Following this amalgam condensation and carving can be completed.

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Indication: classII cavities involving one or both proximal surfaces.

Complex situations like pin amalgam restoration.To remove the matrix, compound can be broken away with a sharp explorer tip and matrix strip can be removed.52

5.T-band matrix system

Preformed T-shaped stainless steel matrix without a retainerLong arm of T-surrounds the tooth and overlaps short arm of T.

The band is adjusted according to circumference of tooth,stabilized by wedging and supported by low fusing compound.

Indication: for class11 cavities involving one or both proximal surfaces of posterior tooth.

Simple and inexpensive .Rapid and easy to apply.

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6.S-shaped matrix band

used for restoring distal part of canine and premolar.

Stainless steel matrix band is taken and twisted like s with the help of mouth mirror handle.

Advantage: it offers the optimal contour for distal part of canine and premolar.

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7.Precontoured matrix

Consists of small, precontoured dead soft metal matrices ready for application to tooth.

They are selected according to the tooth to be restored and wedged to adapt to gingival contour.

Following this, the band is held in place by a flexible metal ring called BiTine ring.

eg:palodent bitine matrix system, composi-tight matrix system.

Used for both amalgam and composite restorations.

Easy to apply and provides slight tooth seperation.

Tight contacts may prevent insertion of band

Expensive.55

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8.Copper band matrix

Copper band of assorted sizes makes excellent matrices.

Cylindrical in shape and can be selected according to the diameter of tooth to be restored.

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58The bands are softened by heating to redness in a flame and quenching in water.

After this the bands can be stretched and shaped with contouring players.

The occlusal height of band is adjusted.With contouring players the band is contoured to reproduce the proper shape of the contact area and the buccal and lingual contours.

After condensation and carving of amalgam the band is left in place it is sectioned and removed in next appointment

Indication: for badly broken teeth especially those receiving pin amalgam restoration.

For complex situations like classII cavities with large buccal or lingual extensions.

Advantage:provide excellent contour.

Disadvantage:time consuming.59

9 Automatrix System The automatrix system is an alternative to a universal retainer.There is no retainer used to hold the band in place. Bands are already formed into a circle and are available in assorted sizes in both metal and plastic. Each band has a coil like autolock loop. A tightening wrench is inserted into the coil and turned clockwise to tighten the band.When finished, the tightening wrench is inserted into the coil and turned counterclockwise to loosen the band.Removing pliers are used to cut the band. 60

Automatrix bands available in thickness of 0.0015 to 0.002 inch.

Available in three widthsNarrow -3/16th inchMedium-1/4th inchWide-5/16th inch

Automate II tightening device used to adjust the loop of the band according to circumference of tooth to be restored.

Shielded nippers-used to cut the autolock loop so that band can be seperated and removed from the tooth after restoration.61

62Indication:complex amalgam restoration where one or more cusps to be replaced.

Advantages: improved visibility due to lack of retainer.Rapid application

Disadvantage:bands are flat and difficult to burnish.expensive

10.Clear plastic matrix

Transparent plastic strips are employed as matrices for tooth coloured restoration.

They allow light to pass through them during polymerisation of composite resin.

They can be of different types:

Celluloid(cellulose nitrate) strips used for silicate cements.

Cellophane(cellulose acetate)used for resins.

Mylar strips used for composite and silicate restorations.

After inserting the composite resin material the matrix is pulled tightly around the tooth following which light curing is done.

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Indication: for small and large class111 and class 1v tooth coloured restoration.

Easy to use Inexpensive.

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11.Transparent plastic crown form matrixCommercially available transparent plastic crown forms

Available in various sizes and contours for anterior tooth.

A suitable crown form can be selected for prepared tooth and trimmed to fit 1mm past the prepared margins

The contact area in the crown form is thinned with an abrasive disk so that once matrix is removed the restoration contacts the adjacent tooth.

The bulk of composite resin is loaded into crown form.

Then it is positioned over the tooth and light curing is done.

After curing the crown form can be slit with a bur and removed.

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Indications:for large class1v cavities.For oblique fractures of anterior tooth.

advantage: easy to useGood contours can be established

DisadvantageTime consuming expensive

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12.Window matrixModification of tofflemire matrix.Used for classV amalgam restoration.The contra angled tofflemire retainer is applied on the lingual side of the tooth.A window is cut in the band slightly smaller than the outline of the cavity.Wedges are placed interproximally to stabilize band.Following this amalgam can be condensed through window and contoured using carvers.67

13.Tin foil matrixused in classv restoration for conventional glass ionomer cements.Tin foil may be preshaped and cut according to the gingival third of buccal and lingual surface of tooth tooth to be restored.The band is adjusted so that it extends 1 to 2 mm circumferentially beyond the cavity margins.This can be adapted on the cavity by means of a tweezer after placing glass ionomer cement.Once the restoration sets the tin foil matrix can be peeled away.68

14.Preformed tranpsarent cervical matrixThese are transparent plastic matrices that are available in various contours or use in anterior and posterior tooth.

Indication: classV restoration with composite resin or glass ionomer restorations.

Provides good contour for restoration.69

70Additional Matrix Systems for Primary TeethA spot-welded band is a form-fitted band placed around a prepared tooth, then removed and placed in a smaller form of a welder that fuses the metal together to make a custom band.

CONSEQUENCE OF NON RESTORING PROXIMAL AREASFood impaction leading to recurrent caries.Change in occlusion and intercuspal relations.Rotation and drifting of teeth.Trauma to periodontium.71

72CONCLUSIONThe clinician should have an adequate knowledge of the anatomical and functional aspects of contacts and contours so as to reproduce them with ideal restorative materials. Extensive knowledge about the matricing serves as a guide to reproduce near to normal contacts between teeth which in turn help to maintain the oral cavity in sound health.Selection of the matrix should be based on its ease of use and efficiency to provide optimum contacts and contours.

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BIBILOGRAPHY

74Textbook of operative dentistry

Vimal k sikriRamya raghuNisha garg

Sturdvents art and science of operative dentistryinternet